package DemoText;

import java.util.Scanner;

/**
 * R 格式
 */
public class P10425 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int i = 0, j = 0;
        int n = in.nextInt();
        String d = in.next();
        int len = d.length(), pos = 0;
        int[] arr = new int[10000000];
        for (i = len - 1, j = 0; i >= 0; i--, j++) {
            if (d.charAt(i) == '.') {
                pos = i;
                j--;
                continue;
            }
            arr[j] = d.charAt(i) - '0';
        }
        int tmp = j - pos - 1;
        while(n != 0) {
            int t = 0;
            for(i = 0; i < j; i++) {
                int x = arr[i] * 2 + t ;
                t = x / 10;
                arr[i] = x % 10;
            }
            if(t == 1) {
                arr[j++] = t;
            }
            n--;
        }
        if(arr[tmp] >= 5) { //如果大于5，进行一次四舍五入
            int t = 1;
            for(i = tmp + 1; i < j; i++) {
                int x = arr[i] + t;
                t = x / 10;
                arr[i] = x % 10;
            }
            if(t == 1) {
                arr[j++] = t;
            }
        }
        for(i = j - 1; i > tmp; i--) System.out.print(arr[i]);
    }
 }
